The Preliminary Simulation Studies, For The Body's Electromagnetic Model

This paper firstly introduced the research progress of biological effects of strong electromagnetic field, focus on introduction of nerve stimulation and heart stimulation caused by the fast switched gradient field of magnetic resonance imaging (MRI) system. Then introduced the finite differential time domain (FDTD) method, especially for its absorption boundary condition(ABC). This paper also analysed and compared four types of special ABCs. Based on a whole body model, we simulated the spatial distributions of specific absorption rate (SARs) excited by the sine currents flowing in gradient coils. Considering the high peak value of induced current in the heart section, a special study of torso-body model containing heart was made in order to calculate the spatial distributions of induced currents around the heart. The result shows that nowadays MRI system can produce induced eddy-currents in human body and the current intensity is very close to the excitation threshold of heart under the worst condition.